FAQ about PAS

Scheer PAS uses BPMN and UML to create microservices that are directly executed without source code generation. We call them xUML services.

With the PAS Designer, you can model your business processes in BPMN, design your forms, add some execution, and compile all to an xUML service. The validation and compilation is done continuously in the background while you are working on your model.

Compiled xUML services, then, can be deployed to and executed by the xUML Runtime. Using the Scheer PAS Analyzer, you can directly debug and analyze your model, not some generated source code.

The Designer allows to create BPMN models in combination with UML execution, Data Mapping and Forms in a way that serves as process documentation, and in the same time as production service.

xUML services are platform independent. Their logic is modeled as flows that are triggered by modeled endpoints, such as REST, Schedulers and Timers.
The (asynchronous) process logic is modeled as BPMN, completed by (synchronous) UML activities that implement the execution.

All that is compiled into a platform independent xUML service repository that translates the modeled logic into an UML state machine. This state machine handles the actual process. Refer to xUML Service State Machines for more details on the state machine and related options.

Go to chapter Technical Concepts in the Designer Guide for more detailed information about the xUML service interface, form communication, or the xUML Runtime architecture and transaction concept.

If you want to use Scheer PAS in the cloud, all you need is an up-to-date web browser on your computer. Scheer PAS offers a variety of interaction options with its user interface ("Rich Internet Application") and uses HTML5.

Therefore, a powerful, modern browser with JavaScript and Websocket support is required to run Process Apps. The network environment must allow SSL and Websocket requests.

Scheer PAS supports the latest versions of the following browsers:

• Google Chrome

• Mozilla Firefox

• Microsoft Edge

Scheer PAS can also be installed "on-Premises" if desired. The product is then set up on a server provided by the customer. The technical platform, database and integration services are provided.

Refer to Scheer PAS System Requirements for details.

Designing xUML services with Scheer PAS Designer is a four-step process:

1. Model your process in BPMN.

2. Design forms that provide and show necessary data.

3. Process the data by adding execution to your BPMN model, and create a service that is ready to deploy.

4. Test your service.

Refer to Development Approach in the Designer Guide for more details.

Processes are based on data that is going in, is processed, and coming out. This data is specified by data types.
Data types can be structured into packages or interfaces. They are defined by classes and their properties, and have related operations and their parameters.

So if you want to start modeling your processes in Scheer PAS, you need to describe the data that is being used during your process.
To do this, you can

• use the built-in Base Types

• import one or more libraries that contain the necessary data types

• create your own data model (implementation) with the Designer

Refer to Concepts of Data Modeling in the Designer Guide for more detailed information.

Scheer PAS Designer comes with a set of adapters that allow you to access a variety of backends via different interfaces.

Some adapters are based on standard interfaces and can be used out of the box. These are

• Apache Kafka Producer Adapter

• Filesystem Adapter

• Flat File Adapter

• JSON Adapter

• Logger Adapter

• Memory Adapter

• MongoDB Adapter

• S3 Adapter

• SQL Adapter

Some adapters are designed to connect to custom interfaces that may vary depending on the backend. These are

• REST Adapter

• SAP Adapter

• URL Adapter

Refer to the related adapter pages for more information on how these adapters can be configured.